Eggs

Eggs laid by females of many different species, including birds, reptiles, amphibians, and fish, have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen (egg white), and vitellus (egg yolk), contained within various thin membranes. Popular choices for egg consumption are chicken, duck, roe, and caviar; but by a wide margin the egg most often humanly consumed is the chicken egg.

Egg yolks and whole eggs store a lot of protein and choline, and are widely used in cooking. Despite the nutritional value of eggs, there are some potential health issues arising out of egg quality, storage, and individual allergies, though these issues are likely exaggerated. The quality and safety of eggs is largely dependent on their production, with pastured eggs considered the best for health, and battery-farmed the worst.

Chickens and other egg-laying creatures are widely kept throughout the world, and mass production of chicken eggs is a global industry. There are issues of regional variation in demand and expectation, as well as current debates concerning methods of mass production, with the European Union planning to ban battery farming of chickens from 2012.